is a company guilty of breach of contract for refusing to pay the final payment due on a company aquisition

Assuming that the company has no defense to the claim of breach of contract (i.e. do not claim that they have already performed, do not claim that the other side is in breach, do not claim that they were defrauded into entering into the contract, do not claim that performance is excused due to the non-occurrence of a condition precedent, etc. etc. etc.), the company Is "guilty" (not really the right word; this isn't a criminal matter) of breach of contract.